Non-patent Documents 1 to 3 disclose passivation techniques to passivate a surface of a Group III-V compound semiconductor to be used in an MISFET (Metal-Insulator-Semiconductor Field-Effect Transistor) by using (NH4)2S, HBr or phosphorous nitride.    Non-patent Document 1: Y. Xuan et al., IEEE Electron Device Lett., 28, 935 (2007)    Non-patent Document 2: Y. Q. Wu et al., IEDM Tech. Dig., 323 (2009)    Non-patent Document 3: H. J. Oh et al., IEDM Tech. Dig., 339 (2009)